fix tests

Author: bnasslahsen

springdoc-openapi-tests/springdoc-openapi-kotlin-webmvc-tests/src/test/resources/results/3.1.0/app3.json

@@ -96,8 +96,7 @@
             "type": "array",
             "items": {
               "type": "string"
-            },
-            "uniqueItems": true
+            }
           }
         },
         "required": [
@@ -106,4 +105,4 @@
       }
     }
   }
-}
+}